TORONTO – Stefanos Tsitsipas’ best-ever run at an ATP World Tour Masters 1000 event continued on Friday when he rallied to upset third-ranked Alexander Zverev 3-6, 7-6 (11), 6-4 and advance to the semifinals of the Rogers Cup in Toronto.

The 19-year-old Greek rising star trailed by a set and a break, but he got back on serve late in the second set and then saved two match points in a marathon tiebreaker before forcing the decider.

The 21-year-old German slammed his racquet to the ground in frustration after missing a cross-court backhand to lose the second set.

Tsitsipas struggled on serve in the final set, but he managed to save eight of the nine break points he faced and broke Zverev’s serve on two occasions to wrap up the victory in two hours and 27 minutes.

For Tsitsipas, who had defeated Austrian world No. 8 Dominic Thiem and 10th-ranked Serbian Novak Djokovic in the two previous rounds, it was his third straight victory over a top-10 opponent.

Before this week, he had never advanced past the second round of one of the nine ATP World Tour Masters 1000 events, which are among the biggest tournaments outside of tennis’ four Grand Slams.

His opponent in Saturday’s semifinals will be South African 2018 Wimbledon runner-up Kevin Anderson, the world No. 6, who brushed aside Bulgaria’s Grigor Dimitrov 6-2, 6-2 on Friday.

The other two men’s singles quarterfinals at this Canadian hard-court event – the Netherlands’ Robin Haase versus Russia’s Karen Khachanov and Spanish world No. 1 Rafael Nadal against Croatian world No. 7 Marin Cilic – will be played Friday night.

The women’s Rogers Cup event also is being played this week in Montreal.